Add base54.reset() to compress tests

Without this reset, char counts bleed to next tests. One test had a bad expect clause.

test/compress/issue-976.js

@@ -84,5 +84,5 @@ eval_mangle: {
             return a + eval('c');
         }
     }
-    expect_exact: 'function f1(n,c,e,a,o){return n("c")+c}function f2(a,b,c,d,e){return a+eval("c")}function f3(a,eval,c,d,e){return a+eval("c")}'
+    expect_exact: 'function f1(n,c,e,a,f){return n("c")+c}function f2(a,b,c,d,e){return a+eval("c")}function f3(a,eval,c,d,e){return a+eval("c")}'
 }

test/run-tests.js

@@ -85,6 +85,7 @@ function run_compress_tests() {
         log_start_file(file);
         function test_case(test) {
             log_test(test.name);
+            U.base54.reset();
             var options = U.defaults(test.options, {
                 warnings: false
             });