[fuzz] Speed up round trip tests

* Enforce smaller maximum values for parameters
* Adjust parameters to the source size

The memory usage is reduced by about 5x, which makes the fuzzers run at
least twice as fast, even more so with ASAN/MSAN enabled.

tests/fuzz/zstd_helpers.h

@@ -21,7 +21,11 @@
 extern "C" {
 #endif
 
-void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, uint32_t *state);
+void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, uint32_t *state);
+
+ZSTD_compressionParameters FUZZ_randomCParams(size_t srcSize, uint32_t *state);
+ZSTD_frameParameters FUZZ_randomFParams(uint32_t *state);
+ZSTD_parameters FUZZ_randomParams(size_t srcSize, uint32_t *state);
 
 
 #ifdef __cplusplus