Reorganize directories (#3462)

* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests

tests/thirdparty/Fuzzer/test/fuzzer-flags.test

@@ -0,0 +1,10 @@
+RUN: LLVMFuzzer-SimpleTest -foo_bar=1 2>&1 | FileCheck %s --check-prefix=FOO_BAR
+FOO_BAR: WARNING: unrecognized flag '-foo_bar=1'; use -help=1 to list all flags
+FOO_BAR: BINGO
+
+RUN: LLVMFuzzer-SimpleTest -runs=10 --max_len=100 2>&1 | FileCheck %s --check-prefix=DASH_DASH
+DASH_DASH: WARNING: did you mean '-max_len=100' (single dash)?
+DASH_DASH: INFO: A corpus is not provided, starting from an empty corpus
+
+RUN: LLVMFuzzer-SimpleTest -help=1 2>&1 | FileCheck %s --check-prefix=NO_INTERNAL
+NO_INTERNAL-NOT: internal flag