tgc-revival: use testresource data for cai2hcl

[zli82016]

1. Inject schema to fake resourcdata used for cai2hcl, so d.Get or similar functions will not return nil.
2. Introduce tgc_ignore_terraform_decoder to ignore decoder during cai2hcl

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[modular-magician]

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terraform-google-conversion: Diff ( 63 files changed, 480 insertions(+), 62 deletions(-))

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

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terraform-google-conversion: Diff ( 65 files changed, 494 insertions(+), 107 deletions(-))

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

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Your PR generated some diffs in downstreams - here they are.

terraform-google-conversion: Diff ( 62 files changed, 440 insertions(+), 104 deletions(-))

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

terraform-google-conversion: Diff ( 62 files changed, 442 insertions(+), 104 deletions(-))

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

terraform-google-conversion: Diff ( 63 files changed, 453 insertions(+), 104 deletions(-))