Fix incorrect code section byte counts in exception handling test

The hand-crafted WASM binary in load_module_with_exception_handling had
an off-by-one in the code section: body size was declared as 7 but the
actual body (local count + try/catch_all/end/end) is only 6 bytes.
This caused the WASM loader to fail with "unexpected end" when it tried
to read past the available bytes.

Fix the body size from 7 to 6 and the code section size from 9 to 8.

Author: sumleo

tests/unit/exception-handling/exception_handling_test.cc

@@ -82,8 +82,8 @@ TEST_F(ExceptionHandlingTest, load_module_with_exception_handling)
         /* Export: "f" = func 0 */
         0x07, 0x05, 0x01, 0x01, 0x66, 0x00, 0x00,
         /* Code section */
-        0x0A, 0x09, 0x01,
-        0x07, 0x00,       /* body size=7, 0 locals */
+        0x0A, 0x08, 0x01,
+        0x06, 0x00,       /* body size=6, 0 locals */
         0x06, 0x40,       /* try (void) */
         0x19,             /* catch_all */
         0x0B,             /* end try */