Increase maximum window size

* Maximum window size in 32-bit mode is 1GB, since allocations for 2GB fail
  on my Mac.
* Maximum window size in 64-bit mode is 2GB, since that is the largest
  power of 2 that works with the overflow prevention.
* Allow `--long=windowLog` to set the window log, along with
  `--zstd=wlog=#`. These options also set the window size during
  decompression, but don't override `--memory=#` if it is set.
* Present a helpful error message when the window size is too large during
  decompression.
* The long range matcher defaults to a hash log 7 less than the window log,
  which keeps it at 20 for window log 27.
* Keep the default long range matcher window size and the default maximum
  window size at 27 for the API and CLI.
* Add tests that use the maximum window size and hash size for compression
  and decompression.

tests/zstreamtest.c

@@ -50,6 +50,7 @@ static const U32 g_cLevelMax_smallTests = 10;
 #define COMPRESSIBLE_NOISE_LENGTH (10 MB)
 #define FUZ_COMPRESSIBILITY_DEFAULT 50
 static const U32 prime32 = 2654435761U;
+static const U32 windowLogMax = 27;
 
 
 /*-************************************
@@ -1380,6 +1381,7 @@ static int fuzzerTests_newAPI(U32 seed, U32 nbTests, unsigned startTest, double
 
                 /* mess with compression parameters */
                 cParams.windowLog += (FUZ_rand(&lseed) & 3) - 1;
+                cParams.windowLog = MIN(windowLogMax, cParams.windowLog);
                 cParams.hashLog += (FUZ_rand(&lseed) & 3) - 1;
                 cParams.chainLog += (FUZ_rand(&lseed) & 3) - 1;
                 cParams.searchLog += (FUZ_rand(&lseed) & 3) - 1;