scripts/oss-fuzz: rename bin/qemu-fuzz-i386

OSS-Fuzz changed the way it scans for fuzzers in $DEST_DIR. The new code
also scans subdirectories for fuzzers. This means that OSS-Fuzz is
considering bin/qemu-fuzz-i386 as an independent fuzzer (it is not - it
requires a --fuzz-target argument). This has led to coverage-build
failures and false crash reports. To work around this, we take advantage
of OSS-Fuzz' filename extension check - OSS-Fuzz will not run anything
that has an extension that is not ".exe":
https://github.com/google/oss-fuzz/blob/master/infra/utils.py#L115

Reported-by: OSS-Fuzz (Issue 26725)
Reported-by: OSS-Fuzz (Issue 26679)
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201101212245.185819-1-alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

scripts/oss-fuzz/build.sh

@@ -91,7 +91,7 @@ make "-j$(nproc)" qemu-fuzz-i386 V=1
 # Copy over the datadir
 cp  -r ../pc-bios/ "$DEST_DIR/pc-bios"
 
-cp "./qemu-fuzz-i386" "$DEST_DIR/bin/"
+cp "./qemu-fuzz-i386" "$DEST_DIR/bin/qemu-fuzz-i386.base"
 
 # Run the fuzzer with no arguments, to print the help-string and get the list
 # of available fuzz-targets. Copy over the qemu-fuzz-i386, naming it according
@@ -104,7 +104,7 @@ do
     # that are thin wrappers around this target that set the required
     # environment variables according to predefined configs.
     if [ "$target" != "generic-fuzz" ]; then
-        ln  "$DEST_DIR/bin/qemu-fuzz-i386" \
+        ln  "$DEST_DIR/bin/qemu-fuzz-i386.base" \
             "$DEST_DIR/qemu-fuzz-i386-target-$target"
     fi
 done