test(es/minifier): Add a test for an invalid issue (#6802)

**Related issue:**
 
 - vercel/next.js#30237 (comment)

Author: kdy1

crates/swc_ecma_minifier/tests/pass-1/regexp/1/input.js

@@ -0,0 +1 @@
+export const foo = new RegExp("")

crates/swc_ecma_minifier/tests/pass-1/regexp/1/output.js

@@ -0,0 +1 @@
+export const foo = RegExp("");