Makefile: T9014: unify test target CPU count and memory size

Test targets had inconsistent --cpu (2/4) and --memory (7/8) values
hardcoded inline. Standardize on TEST_CPUS and TEST_MEM variables:
TEST_CPUS is min(nproc, 4) so hosts with fewer than 4 CPUs don't
request more vCPUs than exist; TEST_MEM is 8GB when the host has at
least 10GB of RAM, otherwise 4GB.

Author: c-po

Makefile

@@ -8,6 +8,13 @@ ISO_PATH := $(build_dir)/live-image-$(ARCH).hybrid.iso
 # amd64 it stays optional.
 UEFI_FLAG := $(if $(filter arm64 aarch64,$(ARCH)),--uefi,)
 
+# Common vCPU count for QEMU test targets, capped at the host's available CPUs
+TEST_CPUS := $(shell printf '%s\n' "$$(nproc)" 4 | sort -n | head -n1)
+
+# Common memory size (GB) for QEMU test targets: 8GB if the host has at
+# least 10GB of RAM, otherwise 4GB
+TEST_MEM := $(shell awk '/MemTotal/{if ($$2/1024/1024 >= 10) print 8; else print 4}' /proc/meminfo)
+
 # Test targets forward extra CLI arguments (e.g. `make test -- --match foo`)
 # to their scripts via $(MAKECMDGOALS). Those extra words are also goals as
 # far as make is concerned, so without this they'd fall through to the `%:`
@@ -28,37 +35,37 @@ all:
 .PHONY: test
 .ONESHELL:
 test:
-	scripts/check-qemu-install --debug --match="$(MATCH)" --smoketest --uefi --cpu 4 --memory 8 --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --match="$(MATCH)" --smoketest --uefi --cpu $(TEST_CPUS) --memory $(TEST_MEM) --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: test-no-interfaces
 .ONESHELL:
 test-no-interfaces:
-	scripts/check-qemu-install --debug --smoketest --uefi --no-interfaces --cpu 4 --memory 8 --huge-page-size 2M --huge-page-count 1800 --isolate-cpus 2-3 --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --smoketest --uefi --no-interfaces --cpu $(TEST_CPUS) --memory $(TEST_MEM) --huge-page-size 2M --huge-page-count 1800 --isolate-cpus 2-3 --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: test-no-interfaces-no-vpp
 .ONESHELL:
 test-no-interfaces-no-vpp:
-	scripts/check-qemu-install --debug --smoketest --uefi --no-interfaces --no-vpp --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --smoketest --uefi --no-interfaces --no-vpp --cpu $(TEST_CPUS) --memory $(TEST_MEM) --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: test-interfaces
 .ONESHELL:
 test-interfaces:
-	scripts/check-qemu-install --debug --match="interfaces_" --smoketest --uefi --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --match="interfaces_" --smoketest --uefi --cpu $(TEST_CPUS) --memory $(TEST_MEM) --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: test-vpp
 .ONESHELL:
 test-vpp:
-	scripts/check-qemu-install --debug --match="vpp" --smoketest --uefi --cpu 4 --memory 8 --huge-page-size 2M --huge-page-count 1800 --isolate-cpus 2-3 --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --match="vpp" --smoketest --uefi --cpu $(TEST_CPUS) --memory $(TEST_MEM) --huge-page-size 2M --huge-page-count 1800 --isolate-cpus 2-3 --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: testc
 .ONESHELL:
 testc:
-	scripts/check-qemu-install --debug --match="!vpp" $(UEFI_FLAG) --cpu 2 --memory 7 --configtest --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --match="!vpp" $(UEFI_FLAG) --cpu $(TEST_CPUS) --memory $(TEST_MEM) --configtest --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: testcvpp
 .ONESHELL:
 testcvpp:
-	scripts/check-qemu-install --debug --match="vpp" $(UEFI_FLAG) --cpu 4 --memory 8 --huge-page-size 2M --huge-page-count 1800 --isolate-cpus 2-3 --configtest --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
+	scripts/check-qemu-install --debug --match="vpp" $(UEFI_FLAG) --cpu $(TEST_CPUS) --memory $(TEST_MEM) --huge-page-size 2M --huge-page-count 1800 --isolate-cpus 2-3 --configtest --iso $(ISO_PATH) $(filter-out $@,$(MAKECMDGOALS))
 
 .PHONY: testraid
 .ONESHELL: