Add the Code -> code mapping for StorageError

[ljian3377]

Fixes #6927 together with the fix in #12150.

[ljian3377]

2020-10-31T15:42:23.7411270Z   1) BlobClient Node.js only
2020-10-31T15:42:23.7414080Z        abortCopyFromClient should failed for a completed copy operation:
2020-10-31T15:42:23.7414640Z 
2020-10-31T15:42:23.7414970Z       AssertionError [ERR_ASSERTION]: false == true
2020-10-31T15:42:23.7416020Z       + expected - actual
2020-10-31T15:42:23.7416340Z 
2020-10-31T15:42:23.7416970Z       -false
2020-10-31T15:42:23.7417360Z       +true
2020-10-31T15:42:23.7417640Z       
2020-10-31T15:42:23.7418470Z       at /Users/runner/work/1/s/sdk/storage/storage-blob/test/node/blobclient.spec.ts:246:7
2020-10-31T15:42:23.7419170Z       at step (/Users/runner/work/1/s/common/temp/node_modules/.pnpm/tslib@2.0.3/node_modules/tslib/tslib.js:140:27)
2020-10-31T15:42:23.7419840Z       at Object.throw (/Users/runner/work/1/s/common/temp/node_modules/.pnpm/tslib@2.0.3/node_modules/tslib/tslib.js:121:57)
2020-10-31T15:42:23.7420570Z       at rejected (/Users/runner/work/1/s/common/temp/node_modules/.pnpm/tslib@2.0.3/node_modules/tslib/tslib.js:112:69)
2020-10-31T15:42:23.7421080Z       at runMicrotasks (<anonymous>)
2020-10-31T15:42:23.7422160Z       at processTicksAndRejections (internal/process/task_queues.js:97:5)

[jiacfan]