Write flash - add dynamic timeout

[r-zlotorzynski]

Fixes a highly compressed file write exception.
Longer time is required with high compression ratio.

[igrr]

Thank you for the PR @r-zlotorzynski!

There is already a commented-out code block related to this a few lines below:

esptool-js/src/esploader.ts

Lines 948 to 957 in ce8f8da

	/*
	let block_uncompressed = pako.inflate(block).length;
	//let len_uncompressed = block_uncompressed.length;
	bytes_written += block_uncompressed;
	if (this.timeout_per_mb(this.ERASE_WRITE_TIMEOUT_PER_MB, block_uncompressed) > 3000) {
	block_timeout = this.timeout_per_mb(this.ERASE_WRITE_TIMEOUT_PER_MB, block_uncompressed);
	} else {
	block_timeout = 3000;
	}*/ // XXX: Partial block inflate seems to be unsupported in Pako. Hardcoding timeout
	const block_timeout = 5000;

I would prefer to solve the problem with that commented out block, if possible. If not possible, we can have an alternative solution, but then the original code block should be removed.

[igrr]

I've implemented the alternative approach in #83.

[igrr]

Solved by #83