Modified and reimplemented FastLanes library in C

There is a background and intro document in src/fl/README.md

The short version is: this change brings a C implementation
of the FastLanes library to Timescale DB. The original idea
is from 'The FastLanes Compression Layout: Decoding >100 Billion
Integers per Second with Scalar Code' by Azim Afroozeh and
Peter Boncz (https://doi.org/10.14778/3598581.3598587)

Our version departs from the original ideas in a few ways:

- instead of having a single 1024 bit virtual register, I
  introduce multiple smaller register widths, that I call
  'tiered FL', the widths are 8, 16, 32, 64, 128 and 256

- we do not have 1024 bit virtual registers

- our implementation relies on C macros, instead of C++
  templates and code generation

The src/fl/README.md file provides more details about the
library.

Co-authored-by: Sven Klemm <31455525+svenklemm@users.noreply.github.com>
Signed-off-by: David Beck <david.beck.priv@gmail.com>

Author: dbeck

tsl/test/src/test_fastlanes.c

@@ -13,36 +13,22 @@
 #include <time.h>
 #include <utils/palloc.h>
 
+TS_FUNCTION_INFO_V1(ts_test_fastlanes);
+
 /*
- * palloc_aligned was added in PG 16. On PG 15 we over-allocate
- * with palloc, manually aligning, and stashing the raw pointer
- * in the slot just before the aligned address so the matching
- * pfree_aligned can recover it. On PG 16+ palloc_aligned
- * is native and regular pfree handles its output
+ * palloc_aligned was added in PG 16. As PG 15 support
+ * is about to be removed, this test is skipped on PG15.
  */
 #if PG_VERSION_NUM < 160000
-static inline void *
-ts_test_palloc_aligned(Size size, Size alignto, int flags)
-{
-	(void) flags;
-	void *raw = palloc(size + alignto + sizeof(void *));
-	uintptr_t aligned =
-		((uintptr_t) raw + sizeof(void *) + alignto - 1) & ~(uintptr_t) (alignto - 1);
-	((void **) aligned)[-1] = raw;
-	return (void *) aligned;
-}
-static inline void
-ts_test_pfree_aligned(void *p)
+
+Datum
+ts_test_fastlanes(PG_FUNCTION_ARGS)
 {
-	pfree(((void **) p)[-1]);
+	PG_RETURN_VOID();
 }
-#define palloc_aligned(size, alignto, flags) ts_test_palloc_aligned((size), (alignto), (flags))
-#define pfree_aligned(p) ts_test_pfree_aligned(p)
+
 #else
 #define pfree_aligned(p) pfree(p)
-#endif
-
-TS_FUNCTION_INFO_V1(ts_test_fastlanes);
 
 /*
  * The below tests have a few goals to achieve, to act as a full
@@ -838,3 +824,5 @@ ts_test_fastlanes(PG_FUNCTION_ARGS)
 	test_w0_coverage();
 	PG_RETURN_VOID();
 }
+
+#endif